Water heater



c. w. DAVIS ET AL 2,335,918

WATER HEATER Filed March 3, 1941 2 Sheets-Sheet 1 Z 1 Mm y W M 4 7 NAG.R

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Dec. 7, 1943.

Dec. 7, 1943. c. w. DAVIS ETAL 2,335,918

WATER HEATER Filed March 3, 1941 Z SheetS-Sheet 2 I INVENTORS COETLHNDW04 v/s.

WHLTEQB ENGH.

A TTOENEY Patented Dec. 7, 1943 UNITED, STATES PATENT OFFICE WATERHEATER tion of Illinois Application March a, 1941, Serial No. 381,422

8 Claims. (Cl. 122-16) The invention pertains to heaters andparticularly to water heaters of the class in whicha tank holding thewater to be heated is provided with connections extending to a heatedpipe or .coil through which the water circulates during the heatingoperation, heating means being provided to. heat the coil or pipe and tothereby heat the ically pertains to water heaters of the general classreferred to, in which a heating flue or flues' extend through the tankand each preferably contains a water heating pipe, the inventionproviding a construction of flue or fiues and heating pipe or pipes suchthat the flue or flues may serve as a chimney for a burner or means usedto heat the water heating pipe or pipes, special devices being employedin the flue or flues to secure prolonged and efficient contact betweenthe hot gases in the flue and the heat absorbing surfaces, to the endthat the heat of the gases will be efficiently absorbed and alsoefficiently conducted to the water to be heated. The inventiongenerically may be used with burners of any type adapted to the purpose,whether using gas, liquid fuel or other fuel, and whether operatingunder pressure on the fuel or air supplied, or both, or under naturaldraft.

An important problem overcome by the invention generically, is theeiflcient absorption of the heat from the hot gases passing through a,flue, the construction being such as to facilitate a relatively longpath of travel of the hot gases in the flue in such a manner that theyare in intimate Wiping engagement with the surfaces of the heatdirecting and/or absorbing devices and also with the inner surface ofthe flue, over a large part of the path of flow of the gases in theflue, but at the same time without detrimental obstruction to said flow.

The invention more specifically, is well adapted for use with burners ofthe natural draft type, for example liquid fuel burners, and it operateseffectively with liquid fuel burners of the wick type in which liquidfuel, for example kerosene, is burned after having its heated vaporintimately mixed with the air required to support the combustion, theflow of the gases in such cases being due largely, if not entirely, tothe draft of the flue. With burners of the natural draft type, it

is essential to employ a chimney to develop the flow of the gases, andfurthermore, the chimney must have a particular net draft for anyparticular burner, to the end that the draft produced on the burner willbe sufficient to promote effective combustion of the fuel, and at thesame time water contained therein. The invention genernot great enoughto interfere with the eflicient burning of the fuel. In its particularembodiment illustrated in the present specification, the considerationsreferred to are taken into account and the water heating surfaces aswell as the heat directing devices in the flue, are particularlyconstructed to not so seriously impede the flow of the hot gases throughthe flue, as to materially interfere with the chimney effect of the fluein producing a satisfactory draft on a liquid fuel burner of the wicktype. In such cases the small flow-impeding effect of the heat directingdevices of the invention, may be compensated for by having the fluesomewhat longer than would be required for an entirely unobstructedchimney for the burner, so that the net draft effect of the flue actingas a chimney, is substantially the draft required by the burner toefliciently burn the liquid fuel; in some cases a draft-controllingdamper may be used to advantage in the flue, particularly where thealtitude of the place of use of the water heater, cannot be definitelydetermined in advance.

To accomplish the results described the heat directing devices arepreferably in the form of spaced metal discs of material having a highdegree of heat conductivity, for example, copper or copper alloy, whichdiscs are preferably provided with vanes extending from their outerperipheries nearly to the central portions of the discs, the vanes ofthe discs being similarly inclined to impart to the gases flowingthrough the flue, a circuitous path of travel through the flue. Theheat-attenuated condition of the gases engaging the vanes, results inpressing the gases upwardly against the lower surfaces of the vanes,

thus bringing the highly heated gases into intimate engagement with thevanes, and the inclined surfaces of thevanes produce a wiping movementof the-gases against the lower surfaces of the-vanes over substantiallythe entire area of each of the discs employed,which results inacircuitous motion of the gases in the flue, the action of the vanes ofeach disc continuing the directive action of the preceding disc on thegasespassing through the flue, so that the gases have a continuouscircuitous movement through the fiue;,

this action, by the inertia of the gases, also presses the gases againstthe inner surface of the flue and produces intimate wiping engagement ofthe gases therewith over a long path of travel through the flue, therebyfacilitating heat transfer to and through the flue. The columnsupporting the vanes is illustrated as a water heating pipe which ispreferably made of material having a high degree of heat conductivity,for example, copper or copper alloy, and the vanes are intimately.connected with the heating pipe preferably by' brazing or soldering, toafford an efficient communication of the heat of the vanes to the pipeand thereby to the water in and flowing through the pipe. The waterheating pipe illustrated, is preferably straight and provided -with anuninterrupted and continuous inner surface, as a result of which thewater heated in the pipe flows rapidly through it without obstruction ofany kind, which greatly increases the emciency of operation ofthe'heater over a period of time by eliminating most of theprecipitation of mineral matter from the water which otherwise wouldoccur, there being no pockets or branches from the pipe to facilitatesluggish movement of the water therein and result in the deposit of saidmineral matter.

It is an object of the present invention generically, to produce a waterheater of the flue type, inwhich a column which may or may not be awater heating pipe as desired, extends through a flue and which isprovided in the flue with heat directing devices of a highly efllcientnature which produce a large area and length of travel of effective andefficient wiping engagement between the hot gases in the flue and theheat absorbing surfaces.

It is a further object of the invention to provide a water heater of thetype described and provided with a water heating pipe and heat directingdevices generically of the kind referred to, in which the water heatingpipe has a straight inner surface which is unbroken throughout theheating zone, facilitating the free flow of water therethrough andsubstantially retarding the precipitation and deposit in the waterheating pipe of mineral matter from water flowing through said pipe.

It is a further object of the invention to produce a water heater of theflue type, which flue is provided with heat directing devices eflectingefiicient heat transfer to the water, and in such a manner that the fluewill eifectively serve as a chimney for a liquid fuel burner of thenatural draft type, and produce a net draft suflicient for effecting theeillcient combustion of the fuel, but insufllcient to too rapidly removethe burning gases from the burner.

It is a further object of the invention to provide a waterheater with awater heating pipe in a flue, which pipe is straight and has acontinuous and unbroken inner surface and which is entirely free fromwater pockets or recesses opening from the pipe, and to provide on theheating pipe, heat conducting and directing metallic vanes inclined toproduce a circuitous flow of the gases in the flue, which vanes extendnearly, if not quite, to the inner surface of the flue, the vanes beingof substantial extent angularly to aiford eflicient heat direction andabsorption, there being preferably a sufficient number of sets of vanesspaced along the pipe, to produce the coordinated relation andmaintaining that re-' tion,

Fig. 3 is a vertical sectional view to an enlarged scale of a part ofthe structure shown in Fig. 2, taken along the line 3-3 of the latterfigure,

Fig. 4 is a horizontal sectional view to an enlarged scale of a part ofthe construction shown in-Fig. 1, taken along the line 4-4 in the latterfigure,

Fig. 5 is a view similar to Fig. 1, showing a portion of a modifiedconstruction of water heater, and

Fig. 6 is a horizontal, sectional view to an enlarged scale, of thestructure shown in Fig. 1, taken along the line G6 in Fig. 1.

Similar numerals refer to similar parts throughout the several views.

As shown in Fig. l, the water heater consists of a cylindrical tank 10of suitable sheet metal having upper and lower end walls Illa and lllbthrough which a cylindrical flue H extends, the flue being rigidlyconnected with said end walls, for example by welding. A water heatingpipe I! extends vertically and centrally through the flue H and isconnected at its upper end by suitable pipe fittings l3 with the upperportion of the tank l0, and at its lower end by suitable pipe fittings Hwith the lower portion of the tank Ill. The pipe connection l3 may alsoserve as the discharge pipe for water delivered from the tank I. Wateris supplied to the tank by a pipe I5 extending through the top wall Illaand nearly to the bottom wall I017.

The tank I0 is surrounded by a cylindrical shell l6 spaced from thetank, suitable insulating material I! being preferably provided betweenthe shell and the tank. The shell l6 extends substantially below thelower end of the tank ill to form a compartment l8 to contain a liquidfuel burner l9 supported on a fuel reservoir 20 movable horizontally inchannel guides II and 22 into and from the compartment I8 through a door23 shown in Fig. 2. The upper end of the flue H is enclosed by a dome 24provided with a baffle 25 in line with an upper discharge opening 26,communicating with a discharge pipe 36, said dome having also sideperforations 21 for the flow therethrough of air to compensate for thedraft of the pipe '36. The pipe 36 is provided with a damper 31 foradjusting the flow into and through said pipe. A second damper 31a isshown in Figs. 1 and 6, to control the discharge from the flue II, toaccurately adjust thedraft efiect of the flue to suit particularconditions of use.

The burner l9 supports a short lower chimney section 28 upon which thelower flanged end of a sleeve 29 rests, which sleeve constitutes acontinuation of the lower end. of the flue ll, so that the draft effectof the flue Ii is exerted on the burner I9. A passageway 30 of smallvertical extent is provided between the lower chimney section 28 and thelower end of the sleeve 29 to admit to the upper portion of thecombustion zone, the air required for complete combustion,

assume which inlet, however, is of sufficiently restricted heightvertically to not materially interfere with the draft action of the flueH, which flue in any event is long enough to compensate for thecheckdraft effect of the passageway 30.

As shown in Fig. 1, the pipe I2 is provided with a plurality of heatdirecting and absorbing devices 3|, of sheet metal and each constructedpreferably asillustrated in Fig. 4 in which said device is shown ascomprising a disc closely fitting the pipe I! and provided with aplurality of radial slits extending from its outer edge nearly to saidpipe, the vanes or baifles 3|a thus formed being bent into an inclinedor oblique position and in the same direction to impart a whirlingmotion to the hot gases passing upwardly in the flue II. The discs 3|are preferably of such diameter as to nearly or quite engage the innersurface of the flue II, it being preferable that the fit of the discs inthe flue shall be sufficiently loose so that by releasing the pipefittings at the ends of the pipe l2, the assembly consisting of the pipeI! and the discs 3| thereon may be removed as a unit from the'flue,which facilitates assembly and replacement if the latter should berequired. I

As a result of the construction described, the only obstruction to thefree flow of the hot gases upwardly in the flue ll, consists of thevanes or baffles 3la on the discs 3|. The thickness of for example bywelding. This holds the insulating material I! in place. and provides aconvenient support to which the shell It may be attached. As shown inFig. 3 the leg 33 which is of channel cross section having filled-inends, has the upper end portions of its legs notched as shown at 330 torest under and engage the lower edge of the side wall lllc of the tank,when the upper end of the leg is in engagement with the member 32, thedepth of the channel legs being suflicient so'that with the upper endportions thereof notched as referred to, the remaining portion of thechannel flts in the angle section of the member 32, thus holding thenotch 33a in engagement'with the lower'edge of the side wall lllc, inwhich position it is secured, for example by bolts 34. The lower edgeportion of the shell I6 is provided withan annular reinforcing band 35to which the lower portion of the leg these vanes, however, may besmall, since they need not be over 1 6" thick, and on account of thevanes being all inclined in the same direction and each contributing itspart to producing the circuitous flow of the gases through the flue ll,

the obstructing effect of the vanes to gas flow through the flue is sosmall as to be readily compensated for by the length of the flue llemployed, which is preferably such as to produce the net draft requiredfor most effective operation of the burner IS. The large area of thevanes 3la, the pressure of the moving gases upon them, and the wipingaction of the gases against the flue of heat from the gases; thewhirling movement also effects a commingling of the ascending gases. Byproviding a multiplicity of similar discs 3| on the pipe l2, asillustrated, and spacing said discs from each other closely enough sothat the vanes on each disc effectively engage the gases leavingthe-next lower disc, the progressive action of extracting the heat fromthe gases delivereddnto the lower end of the flue I I, so efficientlytransfers to the water in the tank the greater part of the heat of thegases, that although the gases delivered into the lower end of the flueH by the burner l9 are intensely hot, the gases delivered from the dome24 are only warm.

As shown in Figs. 1 and 2, the side wall lilo of the tank is continuedbelow the bottom wall lb, and spaced from the shell l6 by an annularmember 32 which as illustrated is an angle bar, and which is rigidlysecured to the side wall lllc,

. able.

ing vanes making a relatively small angle with 33 is preferably secured,the leg extended sufllciently below the shell l8 to provide for the freepasasge of air to the burner around the lower edge of the shell. Each ofthe legs 33 shown in Figs. 1 and 2 is constructed as described inconnection with Fig. 3, and the result is a substantial, reliable andinexpensive support for the water heater.

As illustrated in Fig. 5, the pipe I2 is provided with a plurality ofdiscs 38 similar to the discs 3| and similarly spaced and connected withthe pipe II, the difference being that the vanes 38a of the disc 38 areinclined at a larger angle to a horizontal plane than are the vanes 3|a.This illustrates the adaptability of the invention for use at differentaltitudes, even in cases where definite draft regulation on the burneris desir- Thus, discs 3| as illustrated in Fig. 1, hava horizontalplane, may be used effectively for a zone of altitudes at and notgreatly above sea level, whereas for a zone of high altitudes, such asmountainous locations, discs 38 having vanes making a substantiallylarger angle with a horizontal plane, may be used equally effectively,the vanes 38a affording freer flow of the gases through the flue H, thando the vanes 31a. In either case, the damper 31 controls the flow intoand through the pipe 38 for different discharge stack drafts, and thedamper 31a affords a convenient means for adjusting the net draft effectof the flue l I to a particular amount where such a result is desired.Only part of the water heater construction is shown in Fig. 5, the partsnot shown being preferably substantially the same as shown and describedin connection with Figs. 1 to 3 inclusive.

While we have illustrated our water heater as provided witha liquid fuelburner, it will be understood that the water heater may be used with anysource of heat applicable to the purpose. It will also be understoodthat water heaters in accordance with our invention, may be used for avariety of purposes, for example they may be used as water heaters fordomestic purposes generally, or again, they may be used for spaceheating purposes in systems in which the heating is accomplished by hotwater radiation in the usual manner, or again, our water heaters may beemployed as steam boilers generally, by maintaining the water level inthe heaters sufficiently below the upper ends of the tanks of theheaters to provide spaces for the steam produced.

While we have illustrated our water heaterias provided with a singleheating flue, it will/be understood that where the tanks are of largesize or a relatively large radiation surface is required,

7 described, or their equivalent. Where it is de-,

sired to employ a plurality of flues and particularly where the tank isof small size, it may be advisable under some conditions to dispensewith I the water heating pipes in the flues and make the supportingcolumns of the heat directing devices in the form of solid columns, forwhile such an arrangement may not afiord the emciency per flue that maybe secured with a water heating pipe in the flue, the amount of heattransferred from the hot gases through the wall of the flue to the waterin the tank is so considerable under the action of our improved heatdirecting devices, that satisfactory results may be secured for somepurposes without the use of the water heating pipes in the flues.

Tests of water heaters in accordance with our invention show a highdegree of thermal efficiency of heat absorption by the water, and with-.out noticeable condensation of any kind in the result of whichwater inthe tank in contact with the flue is rapidly heated and given a vigorous,movement upwardly in the tank, thereby minimizing the insulating effectof the fllm or layer of water immediately around the flue.

We are aware that heating experts advance the theory in connection withtransferring heat through a heat conductive wall, that the nature ofthefilms in contact with the surfaces of the wall exercise much greaterresistant efiect to heat transfer, than does the material of the wallitself, so that the material of the wall makes little difference in theeffectiveness of transferring heat, for example from hot gases on oneside of the wall, to a medium, for example water, on the other side ofthe wall. Regardless of theory, our tests indicate that the heattransfer through the flue of the water heater, although said flue be,made of mild steel, is quite effective, and that a substantial part oftheefllciency of heating the water referred to is due to the heattransferred from the hot gases through the flue to the water in thetank. We prefer to make the flue l l with a substantial wall thickness,thereby facilitating the maintaining of the inner surface of the flue inhighly heated condition, which tends to eliminate condensation on saidinner surface. The action of the heat directing devices in the flue Hdoubtless minimizes the resistant effect of gas films on the flue by therapid w ir nseeetle of the gases and pressure thereof against the flue.either preventing the formation of said films or breaking up the sameafter they are formed; and the rapid convection of the water in the tankthat is in contact with the flue, due to the rapid transfer of heat tothe flue, doubtless minimizes the resistant effect of the water fllmaround the flue. In any event, our tests clearly show a high heatingefllciency of the water in the tank, and they further show that the heattransfer through the flue and the heat transfer through the waterheating pipe where the latter is used, are both substantial factors insecuring the results stated.

While we have shown our invention in the particular embodiment abovedescribed, it will be understood that we do not limit ourselves theretoas we may employ equivalents thereof without departing from the scope ofthe appended claims.

'Having thus described our invention, what we claim is a 1. In a waterheater, the combination of a tank having an open flue extendingthroughit, a liquid fuel burner of the wick type at the lower end ofsaid flue and depending for its operation upon a particular amount ofdraft developed in said flue, and devices including a pipe in said fluefor tranfserring heat from within said flue to water in said'tank, thearea of cross-section of the said pipe being substantially less than thearea of cross-section of the space between said pipe and the flue, thelength of said flue and the retarding effect of said devices on flowthrough said flue being so arranged and related that the resultant fluedraft is that required for efficient action of I said burner.

2. In a water heater, the combination 'of a tank having an open flueextending through it,

a liquid fuel burner of the wick type at the lower end of said flue anddepending for its operation upon a particular amount of draft developedin said flue, devices including a pipe in said flue for transferringheat from within said flue to water in said tank, the area ofcrosssection of the said pipe being substantially less than thearea ofcross-section of the space between said pipe and the flue, the length ofsaid flue and the retarding effect of said devices on flow through saidflue being so arranged and related that the resultant flue draft is thatrequired for eiiicient action of said burner, and means for adjustingsaid flue draft, whereby the water heater may be used eflectively underdifferent conditions of atmospheric pressure.

3. As a means for transferring heat from hot gases to water in a tankhaving a vertical and open flue extending through it, which heattransferring means includes in combination a waterheating pipe ofsubstantially smaller diameter than said flue and extending through saidflue and connected at its ends with said tank, the area of cross-sectionof the pipe being substantially less than the area of cross-section ofthe space between the pipe and the flue, and inclined metal vanessecured to and extending laterally from said pipe in said flue andspaced longitudinally of said pipe, said vanes being in a plurality ofgroups, each group being substantially in a plane perpendicular to theaxis of the pipe, said pipe having an uninterrupted and continuous innersurface, the vanes of each group covering substantially all of theangular extent around the pipe.

4. As a means for transferring heat from hot gases to water in atank-having a vertical and open flue extending through it, which heattransferring means includes in combination a waterheating pipe ofsubstantially smaller diameter than said flue and extending through saidflue andconnected at its ends with said tank, the area of cross-sectionof the pipe being substantially less than the area of cross-section ofthe space between the pipe and the flue, and inclined from said pipe insaid flue and spaced longitudinally of said pipe, said vanesbeing in aplurality pipe having an uninterrupted and continuous inner surface, thevanes of each group covering substantially all of the angular extentaround the pipe, said pipe having separable connection with said tank,and said pipe and said vanes comprising ,a unitary structure readilyinsertible into and removable from said flue.

5. As a means for transferring heat from hot gases to water in a tankhaving a vertical and open flue extending through it, which heattransferring means includes in combination a waterheating pipe ofsubstantially smaller diameter than said flue and extending through saidflue and connected at its ends with said tank, the area of cross-sectionof the pipe being substantially less than the area of cross-section ofthe a liquid fuel burner of the wick type requiring a particular amountof draft for its effective operation, which tank has an open heatingflue extending vertically therethrough to serve as a chimney for saidburner, which heating means includes in combination a water-heating pipeof substantially smaller diameter than said flue and space between thepipe and the flue, and inclined metal vanes secured to and extendinglaterally from said pipe in said flue and spaced longitudinally of saidpipe, said vanes being in a plurality of groups, each group beingsubstantially in a plane perpendicular to the axis of the pipe, saidpipe having an uninterrupted and continuous inner surface, the vanes of.each group covering substantially all of the angular extent around thepipe, said vanes comprising round sheet metal discs cut radially andbent to similar inclinations between said cuts to form said vanes.

6. As a means for heating water in a tank by a liquid fuel burner of thewick type requiring a particular amount of draft for its effectiveoperation, which tank has an open heating flue extending verticallytherethrough to serve as a chimney for said burner, which heating meansincludes in combination a water-heating pipe of substantially smallerdiameter than said flue and extending through said'flue and connected atits ends with said tank, the area of cross-section of the pipe beingsubstantially less than the area of cross-section ofthe space betweenthe pipe and the flue, and inplined metal vanes secured to and extendinglaterally from said pipe in said flue and spaced longitudinally of saidpipe, said vanes being in a plurality of groups, each group beingsubstantially in a plane perpendicular to the axis of the pipe, saidpipe having an uninterrupted and continuous inner surface, the vanes ofeach group covering substantially all of the angular extent around thepipe, said flue being of such height in cooperation with thedraft-retarding effect of said vanes as to produce substantially theparticular amount ofdraft required for effective operation of theextending through said flue and connected at its ends with said tank,the area of cross-section of the pipe being substantially less than thearea of cross-section of the space between the pipe and the flue, andinclined metal vanes secured to and extending laterally from said pipein said flue and spaced longitudinally of said pipe, said vanes being ina plurality of groups, each group being substantially in a planeperpendicular to the axis of the pipe, said pipe having an uninterruptedand continuous inner' surface, the vanes of each group coveringsubstantially all of the angular extent around the pipe, said flue beingof'such height in cooperation with the draftretarding efiect of saidvanes as to produce substantially the particular amount of draft re-' 1tion, which tank has an open heating flue extending verticallytherethrough to serve as a chimney for said burner, which heating meansincludes in combination a water-heating pipe of substantially smallerdiameter than said flue and extending through said flue and connected atitsv ends with said tank, the area of cross-section of the pipe beingsubstantially less than the area of cross section of the space betweenthe pipe and theflue, and inclined metal vanes secured to and extendinglaterally from said pipe in said flue and spaced longitudinally of saidpipe, said vanes being in a plurality of groups, each group beingsubstantially in a plane perpendicular to the axis of the pipe, saidpipe having an uninterrupted and continuous inner surface, the vanes ofeach group covering substantially all of the angular. extent around thepipe, said flue being.

of such height in cooperation with the draftretarding effect of saidvanes as to produce substantially the particular amount of draftrequired for effective operationof said burner, said vanes comprisinground sheet metal discs cut radially and bent to similar inclinationsbe-- tween said cuts" to form said vanes.

CORTLAND w. DAVIS. WALTER a. m en.

